Developer for surface-and internalimage silver halide photographic materials

ABSTRACT

A NOVEL DEVELOPING SOLUTION COMPRISING A 3-PYRAZOLIDONE, AN ASCORBIC ACID, A THIONE OR THIOL SUBSTITUTED NITROGEN-CONTAINING HETEROCYLIC COMPOUND AND AN ALKALI METAL IODIDE IS AN EXCELLENT DEVELOPER COMPOSITION FOR INTERNAL-AND/OR SURFACE-SENSITIVE SILVER HALIDE PHOTOGRAPHIC MATERIALS.

United States Patent 3,826,654 DEVELOPER FOR SURFACE- AND INTERNAL- IMAGE SILVER HALIDE PHOTOGRAPHIC MATERIALS George Raymond Weiss and John Oliver Helling, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y.

Filed June 1, 1971, Ser. No. 148,771 Int. Cl. G03c 5 /30 U.S. Cl. 96-66 HD 16 Claims ABSTRACT OF THE DISCLOSURE A novel developing solution comprising a 3-pyrazolidone, an ascorbic acid, a thione or thiol substituted nitrogen-containing heterocyclic compound and an alkali metal iodide is an excellent developer composition for internal-and/or surface-sensitive silver halide photographic materials.

BACKGROUND OF THE INVENTION Field of the Invention This invention relates to photographic materials and their use. The invention especially relates to photographic developer solutions and to the processing of electromagnetic radiation sensitive photographic elements. In one aspect, this invention relates to the processing of photographic elements comprising surface sensitive and/0r internally sensitive silver halide materials. In another aspect, this invention relates to a total developer composition which can efliciently develop both internal latent images and surface latent images.

Description of the Prior Art In the field of photography it is known that surface latent images are developable by a surface developer, i.e. one that has no solvent for silver halides, such as sodium thiosulfate, and/or no surface etchants, in etching amounts, such as potassium iodide. Internal latent images are generally not developable by surface developers since the internal latent images are inaccessible to the surface developers. However, the internal images can be developed if the developer composition comprises a suitable silverhalide solvent, such as sodium thiosulfate, or a silver halide etchant, such as an iodide, which promotes the cracking of the surface of the silver halide grain, thereby causing the internal latent image to become accessible to the developer composition.

The addition of an alkali metal iodide or silver halide solvents to silver halide developing solutions is described in, for example, Mees and James, The Theory of the Photographic Process, 3rd Edition, The MacMillan Co., New York, 1966 at page 150, and T. H. James, Photographic Science and Engineering, Volume 7, page 304,

It is generally known that the presence of a silver halide cracking agent or silver halide solvent in a surface developer can detrimentally affect the developing capabilities of the developer. It is also known that internal-image developing solutions may develop internal-image emulsions at a relatively slow developing velocity or speed.

It is apparent that there is a need for an improved internal-image developer. It is further apparent that the photographic art would benefit by a developer composition which possesses the capability of effectively develop- 3,826,654 Patented July 30, 1974 ternal-image emulsion is one which forms latent images predominately on the surface of the silver salt grains.

It is, therefore, an object of this invention to provide a novel photographic silver salt developer capable of developing both internal latent images and external latent images.

It is another object to provide a novel silver salt developer capable of developing surface sensitive silver salt emulsions which developer is not detrimentally affected by the presence of a silver salt etchant.

It is yet another object of the invention to provide a novel silver salt developer which is capable of developing internal latent images and which exhibits improved photographic properties.

It is still another object of the invention to provide a novel process for the development of exposed photographic products.

These and other objects are accomplished by the invention as described herein.

SUMMARY OF INVENTION In accordance with this invention, improved photographic developer compositions are provided which comprise a 3-pyrazolidone, an ascorbic acid, a thione or thiol substituted nitrogen containing heterocyclic compound and an alkali metal iodide. The utility of these novel developing solutions as either an internal developer or a surface developer is unexpected since it is well known that etchant amounts of an alkali metal iodide such as, for example, potassium iodide, will detrimentally affect the sensitometric properties of a surface developer composition. The developer compositions are unexpectedly faster than prior art internal developer solution. The compositions allow for continuous or noncontinuous processing of photographic materials without the necessity of changing the developing solution whether the materials being developed comprise surface sensitive or internal sensitive silver halide grains.

DESCRIPTION OF THE PREFERRED EMB'O'DTMI'EII'I In an embodiment, an aqueous, high pH developer composition is provided comprising a 3-pyrazolidone, an ascorbic acid, an alkali metal iodide and a nitrogen containing heterocyclic thione or thiol compound with potassium iodide.

A wide variety of heterocyclic thiol or thione compounds may be employed in accordance with the invention. Illustrative of a preferred group of heterocyclic thione or thiol compounds are those: represented by the formulas:

N=C-SH or wherein Z represents ae non-metallic atoms necessary to complete a heterocyclic nucleus, the nucleus preferably containing from 5 to 6 atoms in the ring and more preferably 5 atoms in the ring. It should be further understood that the heterocyclic ring structure can be fused to other ring systems as illustrated by mercaptobenzothiazole or tetrazaindene-thiol.

Typical thione or thiol compounds which can be employed in accordance with the invention are:

1,2-dihydro-2-mercapto-l-pheny-5.H-tetrazole, 5-methyloxazoline-2-thiol 2-mercapto-5-phenyl-1,3,4-oxadiazole, 1-(3-caprimido)-phenyl-S-mercaptotetrazole,

1- 3-pelargonamide -phenyl-5-me:rcaptotetrazole, 2,6-dimethyl-1,3,3a,7-tetrazaindene-4-thiol,'

- ,3 Z-mercaptobenzoxazole, 1phenyl-S-mercaptotetrazole, -ethyl-6-methyl-1,2,3a,7-tctrazaindene-4-thiol Z-mercaptoimidazole, 4-methyl-1,2,3a,7-tetrazaindene-6-thio, .4-thiono-4a-azanaphthalene, 2-mercapto-fl-naphthoxazole-Z-thionothiazolidone, 4-mercapto-1-thia-3,5,7-triazaindene, 4hydroxy-6-methyl-1,2,3a,7-tetrazaindene-3-thiol, 3-mercapto-1,2,4-triazole, 2-mercapto-5-(p-hydroxy-phenyl)-1,3,4-oxadiazole, Z-mercapto benzothiazole, l methyl-1,2,3,6-tetrahydro-1,3,5-triazine-4-thiol, or 4-phenyliminothiourazole, and the like.

A number of such suitable mercapto heterocyclic nitrogen compounds are disclosed in Tregillus et al. U.S. Pat. 3,017,270, issued Jan. 16, 1962.

Preferably the thiol or thione heterocyclic compounds employed in accordance With theinvention are S-mercaptotetrazoles, oxazoline-Z-thiols, tetrahydro-1,3,5-triazine-4-thiols or iminothiourazoles. Accordingly, in an embodiment of this invention developer compositions are provided comprising a 3-pyrazolidone, an ascorbic acid, an alkali metal iodide and one of l-phenyl-S-mercaptotetra'zole, S-methyloxazoline-Z-thiol, 1-methyl-1,2,3,6-tetrahydro-1,3,5-triazine 4 thiol or 4-phenyliminothiourazole.

In a particularly preferred embodiment l-phenyl-S-mercaptotetrazole is employed in combination with potassium iodide.

In still another preferred embodiment the compositions are high pH, aqueous developer compositions comprising 1-phenyl-3-pyrazolidone, sodium isoascorbate and the combination of 1-phenyl-5-mercaptotetrazole with potassium iodide.

In still another embodiment of the invention exposed photograph silver halide elements are developed in the presence of the herein described developer solutions. A particularly preferred embodiment of the inventive process is the development of an exposed internal light sensi tive photographic silver bromoiodide emulsion particularly those silver bromoiodide emulsions in which iridium is occluded in the silver salt grains. Good results, however, can also be obtained with silver halide grains having occluded lead ions, bismuth ions, gold ions, osmium ions, palladium ions, rhodium ions and the like.

As already indicated, potassium iodide is preferably employed in the prictice of this invention, however other alkali metal iodide can be employed such as for example, sodium iodide. Ammonia iodide can also be employed hence ammonia iodide is to be understood to be included within the generic meaning of alkali iodide. The iodide is typically present in etchant amounts and typically from 0.1 to about grams per liter of developer composition. In an especially preferred aspect of the invention potassium iodide can be present in a range of from about 0.4 to about 0.6 grams per liter of developer composition and preferably about 0.5 grams per liter of developer composition. The concentrations of the cracking or Keinblosslegung addends (H. Luppo-Cramer, Die Grundlagen der Photographischen Negativverfahren, Eders Handbuch, II, part I, Wilhelm Knapp Verlag, Halle (Saale) (1927), pp. 220-222 and chapter 11) should generally not be main tained at very low levels in order that the composition eificiently function as an internal developer and the unexpected improvements in the surface development capabilities be maintained.

The novel composition of the invention, while in operation, typically should be maintained at a high pH. It is generally desirable that the pH be maintained at at-least about 12, preferably 12 to about 14 and more preferably about 13 to 14.

The compositions of this invention include an ascorbic acid, e.g. ascorbic acid or its derivatives. Ascorbic acid "4 derivatives which are illustrative of those that can be employed in accordance with the invention includez l-ascorbic acid, l-erythroascorbic acid 6-desoxy-1-ascorbic acid, d-glucoascorbic acid, l-rharnnoascorbic acid, l-fucoascorbic acid, d-glucoheptoascorbic acid,

and isoascorbic acid and the like.

As contemplated by the invention either the dor 1- compounds alone can be employed or mixtures thereof. In a preferred embodiment salts of ascorbic acid are typically employed, such as for example, alkali metal salts such as sodium isoascorbate. The ascorbic acid derivatives and their sugar analogs which can be employed are described in James and Reynolds U.S. Pat. 2,688,549, issued Sept. 7, 1954.

In accordance with this invention 1-phenyl-3-pyrazolidone is preferably employed with ascorbic acid; however a wide variety of 3-pyrazolidones can be employed such as, for example, 1-phenyl-4,4-dimethyl-3-pyrazolidone, and the like. Various 3-pyrazolidones Which can be employed are described, for example, in U.S. Pat. 2,772,282 of Allen et al., issued Nov. 27, 1956, and U.S. Pat. 3,221,- 023 of DeMarle et al., issued Nov. 30, 1965.

The developing solutions of this invention operate efiiciently as surface developers (the developer will reveal as much surface image as would be obtained from a 4 minute development in a conventional N-methyl-p-aminophenyl sulfatehydroquinone developer) and additionally unexpectedly produce a more desirable image tone and improvement in over-all density. Thenovel composition as an internal developer is surprisingly superior than other known internal developers, for example, the developers in accordance with the invention can obtain from the internal emulsion over 1.0 log E more internal sensitivity than other known internal developers.

Typically, in accordance with the invention the developer solution will contain other ingredients in addition to those described above such as, for example, potassium bromide, sodium sulfite and an alkaline compound such as sodium hydroxide.

The developer compositions of this invention can be employed in developing a variety of silver halide emulsions. The silver halide emulsions employed can comprise silver chloride, silver bromide, silver bromoiodide, silver chlorobromoiodide or mixtures thereof. The emulsions can be coarse or fine grain and can be prepared by any of the well-known procedures, e.g. single jet emulsions, double jet emulsions, such as Lippmann emulsions, ammonlacal emulsions, thiocyante or thioether ripened emuls1ons such as those described in Nietz et al. U.S. Pat. 2,222,264 issued Nov. 19, 1940; Illingsworth U.S. Pat. 3,320,069 issued May 16, 1967; and McBride U.S. Pat. 3,271,157 issued Sept. 6, 1966. Surface image emulsions can be used or internal image emulsions such as those described in Davey et al. U.S. Pat. 2,592,250 issued May 8, 1952; Porter et al. U.S. Pat. 3,206,313 issued Sept. 14, 1965; Berriman U.S. Pat. 3,367,778 issued Feb. 6, 1968; and Bacon et al. U.S. Pat. 3,447,927 issued June 3, 1969. If desired, mixtures of surface and internal image emulsions can be used as described in Luckey et al. U.S. Pat. 2,996,382 issued Aug. 15, 1961. Negative type emulsions can be used or direct positive emulsions such as those described in Leermakers U.S. Pat.'2,184,0l3 ssued Dec. 19, 1939; Kendall et a1. U.S. Pat. 2,541,472 ssued Feb. 13, 1951; Berriman U.S. Pat. 3,367,778 ssued Feb. 6, 1968; Schouwenaars British Pat. 723,019 issued Feb. 2, 1955; Illingsworth et al. French Pat/1,520,- 821 issued Mar. 4, 1968; Ives U.S. Pat. 2,563,785 issued Aug. 7, 1951; Knott et a1. U.S. 2,456,953 issued Dec. 21, 1948, and Land U.S. Pat. 2,861,885 issued Nov. 25, 1958. The emulsions can be regular grain emulsions such as the type described in Klein and Moisar, J. Phot. Sci., vol. 12, No. 5, September/ October 1964, pp. 242-251.

' The emulsions developed in accordance with this invention can be sensitized with chemical sensitizers, such as with reducing agents; sulfur, selenium or telluriu'm compounds; gold-platinum or palladium compounds; or combinations of these. Suitable procedures are described in Sheppard et al. U.S. Pat. 1,623,499 issued Apr. 5, 1917; Waller et al. U.S. Pat. 2,399,083 issued Apr. 23, 1946; McVeigh U.S. Pat. 3,297,447 issued Jan. 10, 1967; and DunnU.S. Pat. 3,297,446 issued Jan. 10, 1967.

The silver halide emulsions developed in accordance with this invention cancontain speed increasing compounds sucha's polyalkylene glycols, cationic surface active agents and thioe'thers or combinations of these as described in Piper U.S."Pat."2,886,437 issued May 12, 1959; Dann et-al. U.S.-Pat. 3,046,134 issued July 24, 1962; Carroll et al. U.S. Pat. 2,944,900 issued'luly 12, 1960; and Goife U.S. Pat. 3,294,540 issued Dec. 27, 1966.

The silver halide emulsions developed in accordance with the practice of this invention can be protected against the production of fog and can be stabilized against loss of sensitivity during keeping. Suitable antifoggants and stabilizers' each used alone or in combination include thiazolium salts described in Brooker et al. U.S. Pat. 2,131,- 038 issued Sept. 27, 1938, and Allen et al. U.S. Pat. 2,694,- 716 issued Nov. 16, 1954; the azaindenes described in Piper U.S. Pat. 2,886,437 issued May 12, 1959; and Heimback'et al.U.S. Pat. 2,444,605 issued July 6, 1948; the mercury" salts as described in Allen et al. U.S. Pat. 2,728,663 "issued Dec. 27, 1955;the urazoles described in Anderson et al. U.S. Pat. 3,287,135 issued Nov. 22, 196 6;the sulfocatechols described in Kennard et al. U.S. Pat. 3,236, 652 issued Feb. 22, 1966; the oximes described inCarroll etal. British Pat- 623,448 issued May 18, 1949; nitron; nitroindaz oles; the mercaptotetrazoles described in Kendall et al. U.S. Pat. 2,403,927 issued July 16, 1946; Kennard et al. U.S. Pat. 3,266,897 issued Aug. 16, 1966, and Luckey et al.. .U.S. Pat. 3,397,987 issued Aug. 20,

1968; the polyvalentmetal saltsdescribed in Jones U.S.

Pan-2,839,405 issued June'17, 1958 the thiuronium salts described in Herz et al. U.S. Pat. 3,220,839 issued Nov. 30; 1965; the palladium, platinum and gold salts described in Trivelli et al. U.S. Pat. 2,566,263 issued Aug. 28,1951, and Yutzy et al. U.S..Pat. 2,597,915 issued May 27,1952. I The photographic and other hardenable layers developed in accordance with the practice of this invention can be hardened by various organic or inorganic hardeners, alone or in combination, such as the aldehydes, and blocked aldehydes, ketonesjcarboxylic and carbonic acid derivatives, sulfonate esters.- sulfonyl halides and vinyl sulfonyl ethers, active halogen compounds, epoxy compounds, aziridines, active olefins, isocyanates, carbodiimides, and polymeric hardeners such as oxidized polysaccharities like dialdehyde starch and oxyguar gum and the like. The photographic emulsions and elements developed in accordance with the practice of the invention can contain various colloids alone or in .combination as vehicles, binding'agents and various layers. Suitable hydrophilic materials include both naturally-occurring substances such as proteins, for example, gelatin, gelatin derivatives, cellulose derivatives, polysaccharides such as dextran, gum arabic and the like; and synth'etic polymeric substances such as water' soluble polyvinyl compounds like poly(vinylpyrrolidone), acrylamide polymers and the like.

The photographic emulsions and elements developed in accordance with the practice of the invention can also contain alone or in combination with hydrophilic, water permeable colloids, other synthetic polymeric compounds such as dispersedvinyl compounds such as in latex form and particularly those which increase the dimensional stability of thephotographic materials. Suitable synthetic polymers include those described, for example, in Nottorf U.S. Pat. 3,142,568 issued July 28, 1964; White U.S. Pat. 3,193,386 issued July 6, 1965; Houck et-al. U.S. Pat. 3,062,674 issued Nov. 6, 1962; Houck et al. U.S. Pat. 3,220,844 issued Nov. 30, 1965; Ream et al. U.S. Pat. 3,287,289 issued Nov. 22, 1966; and Dykstra U.S. Pat. 3,411,911 issued Nov. 19, 1968; particularly effective are those water-insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates, those which have crosslinking sites which facilitate hardening or curing, those having recurring sultobetaine units as described in Dykstra Canadian Pat. 774,054.

The photographic elements used in this invention can contain brightening agents including stilbenes, triazines, oxazoles and coumarin brightening agents. Water soluble brightening agents can be used such as those described in Alberz et al., German Pat. 972,067 and McFall et al., U.S. Pat. 2,933,390 issued Apr. 19, 1960 or dispersions of brighteners may be used such. as those described in Jansen German Pat. 1,150,274, Oetiker et al., U.S. Pat. 3,406,070 issued Oct. 15, 1968 and Heidke French Pat. 1,530,244.

Spectral sensitizing dyes can be used conveniently to confer additional sensitivity to the light sensitive silver halide emulsion of the multilayer photographc elements developed in accordance with the practice of the invention. For instance, additional spectral sensitization can be obtained by treating the emulsion with a solution of a sensitizing dye in an organic solvent or the dye can be added in the form of a dispersion as described in Owens et al. British Pat. 1,154,781 issued June 11, 1969. For optimum results, the dye is either added to the emulsion as a final step or at some earlier stage.

Sensitizing dyes useful in sensitizing such emulsions are described, for example, in Brooker et al. U.S. Pat. 2,526,632 issued Oct. 24, 1950; Sprague U.S. Pat. 2,503,- 776 issued Apr. 11, 1950; Brooker et al. U.S. Pat. 2,493,- 748 issued Jan. 10, 1950; and Taber et al. U.S. Pat. 3,384,486 issued May 21, 1968. Spectral sensitizers which can be used include the cyanines, merocyanines, complex (tri or tetranuclear) merocyanines, complex (tri or tetranuclear) cyanines, holopolar cyanines, styryls, hemicyanines (e.g. enamine hemicyanines), oxonols and hemioxonols.

Dyes of the cyanine classes can contain such basic nuclei as the thiazolines, oxazolines, pyrrolines, pyridines, oxazoles, thiazoles, selenazoles and imidazoles. Such nuclei can contain alkyl, alkylene, hydroxyalkyl, sulfoalkyl, carboxyalkyl, aminoalkyl and enamine groups and can be fused to carbocyclic or heterocyclic ring systems either unsubstituted or substituted with halogen, phenyl, alkyl, haloalkyl, cyano, or alkoxy groups. The dyes can be symmetrical or unsymmetrical and can contain alkyl, phenyl, enamine or heterocyclic substituents on the methine or polymethine chain.

The merocyanine dyes can contain the basic nuclei mentioned above as well as acid nuclei such as thiohydantoins, rhodanines, oxazolidenediones, thiazolidenediones, barbituric acids, thiazolineones, and malononitrile. These acid nuclei can be substituted with alkyl, alkylene, phenyl, carboxyalkyl, suifoalkyl, hydroxyalkyl, alkoxyalkyl, alkylamino groups, or heterocyclic nuclei. Combinations of these dyes can be used, if desired. In addition, supersensitizing addenda which do not absorb visible light can be included, for instance, ascorbic acid derivatives, azaindenes, cadmium salts, and organic sulfonic acids as described in McFall et al. U.S. Pat. 2,933,- 390 issued Apr. 19, 1960, and Jones et al. U.S. Pat. 2,937,089 issued May 17, 1960.

This invention can be used with elements designed for color photography, for example, elements containing color-forming couplers such as those described in Frohlich et al., U.S. Pat. 2,376,679 issued May 22, 1945; Jelley et al., U.S. Pat. 2,322,027 issued June 15, 1943; Fierke et al., U.S. Pat. 2,801,171 issued July 30, 1957; Godowsky US. Pat. 2,698,794 issued Jan. 4, 1955; Barr et al. US. Pat. 3,227,554 issued Jan. 4, 1966; and Graham et a1. U.S. Pat. 3,046,129 issued July 24, 1962; or elements to be developed in solutions containing color-forming couplers such as those described in Mannes et al., US. Pat. 2,252,718 issued Aug. 19, 1941; Carroll et al., US. Pat. 2,592,243 issued Apr. 18, 1952; and Schwan et al., US. Pat. 2,950,970 issued Aug. 30, 1966; and in falsesensitized color materials such as those described in Hanson US. Pat. 2,763,549, issued Sept. 18, 1956.

The concentration of 1-phenyl-3-pyrazolidone can typically be in a range of from about .006 moles to about .12 moles per liter of developer solution and preferably about .06 moles/l. The concentration of ascorbic acid can typically be in a range of from about .05 moles to about .40 moles per liter of developing solution and preferably about .20 moles/l. The potassium iodide-thione or thiol substituted heterocyclic compound ratio can be in a range of about 9:100 to about 600:1 and preferably about 2:1.

In accordance with a preferred embodiment of this invention the developing solution of the invention is an aqueous solution consisting essentially of about .06 moles 1-pheny1-3-pyrazolidone, about .20 moles sodium isoascorbate, about .75 moles sodium hydroxide, about .04 moles potassium bromide, about .16 moles sodium sulfite, about .0014 moles 1-phenyl-4-mercaptotetrazole, about .003 moles potassium iodide per liter of solution. The Alkali metal iodide concentration can be within the range of about 0.002 to about 0.06 mole per liter of developing solution.

The following examples are included for further understanding of the invention.

EXAMPLE I Illustration of Total Development The developer solution of the invention (hereinafter referred to as Developer A is prepared to contain:

Developer A:

Distilled water to 1.0 1.

A known and popularly employed surface developer (Kodak Developer D-19) (hereinafter referred to as Developer B) is prepared to contain:

Developer B: G. N-Methyl-p-aminophenol sulfate 2.0 Sodium sulfite, desiccated 90.0 Hydroquinone 8.0 Sodium carbonate, monohydrate 52.5 Potassium bromide 5.0

Distilled water to 1.0 1.

Two photographic emulsions are prepared as follows: Emulsion A.A surface sensitive gelatino, cubicmonodispersed photographic silver bromoiodide emulsion (2.5 mole percent iodide) having an average grain size of about 0.2 micron is prepared by simultaneously adding (1) an aqueous solution'of potassium bromide and potassium iodide and (2) an aqueoussolutionof silver nitrate to a rapidly agitated aqueous gelatin solution. at a temperature of C. and a controlled pAg of 8.9'for a period of about 35 minutes. The emulsion is then cooled to 40 C., and sufficient gelatin added to give an 8 per: cent gelatin solution, then chill-set, shredded and washed in the conventional manner. Emulsion B.An internally sensitive emulsion containing iridium ions occluded in the silver halide core is prepared in accordance with the procedure of Emulsion A with the exception that the agitated gelatin solution contains 107 mg. of potassium chloroiridite perv silver mole. A sample of Emulsion B is reduction and gold fogged on the grain surface according to the procedure for Emulsion B of Example V'of Illingsworth US. Pat. 3,501,306 hereby incorporated by reference. The surface and in ternally sensitive emulsion is coated on a cellulose acetate support at 120 mg. silver and 178 mg. gelatin per square foot and dried in the conventional manner. Samples of the dried coating are exposed through a graduated neutral density continuous wedge on an Eastman 1B Sensitometer having a 500 w. tungsten light source. Separate exposed samples are developed, fixed and washed. The developer employed andconditions of development are summarized in Table I.

TABLE I (Emulsion B) Time Tempera- Devel- Addendum to. Sample (min.) ture( O.) oper developer 4 20' B 0.5 g./1. KI

4 20 B 10.0 g./l. NaSaOa The results of developing the emulsions are graphically illustrated in the H and D curve shown in FIG. I. Sample 1 corresponding to curve one provides a substantially flattened curve. The substantially flattenedlcurve shows that both surface and internal development are substantially equally occurring when employing the developer solution of this invention. Curve 2 corresponding to Sample 2 is the normal H and D curve obtained from an emulsion which has been reduction and gold fogged on the grain surface and developed in a conventional surface developer. Both curves 3 and 4 corresponding to Samples 3 and 4 illustrate that when either KI or sodium thiosulfate are incorporated in a conventional surface developer the surface development is drastically and detrimentally affected.

EXAMPLE II Efiiciency as a Surface Developer Emulsion A is sulfur and gold sensitized by heating the emulsion to C. for 60 minutes in the presence of 10.5 mg./Ag mole potassium chloroaurate and 12.5 mg./Ag mole sodium thiosulfate. A second portion of Emulsion A is surface sensitized as described for Emulsion B in Example V of US. Pat. 3,501,306 of Illingsworth. This emulsion contains 500 mg./mole Ag of 1,3,- diethyl-1'-methyl 2' phenylimidazo[4,4-b]quinoxolino- 3'-indolocarbocyanine iodide. The separate emulsions are each coated on a cellulose acetate support at mg. silver and 352 mg. gelatin per square foot and dried in a conventional manner. The dried coatings are exposed and processed as in Example I. The results of exposure and processing are summarized in Table II.

TABLE II Dev. B plus Dev. B plus Dev. A Dev. B K1 (.5 g.ll.) NazSzOa (10 g./l.)

Rel. Rel. Rel. Rel. Emulsion A sensitization speed Dmax speed Dmlx speed Dine: speed D...

Sulfur plus gold 100 2.00 151 1. e0 7 0.38 69 1.48 Reduction plus gold fogged- 100 1. 42 91 0. 84 No image No image The results illustrate that Developer A is adequately efiicient as surface developer whereas Developer B, the conventional surface developer, is detrimentally atfected by the presence of either KI or' Na s O EXAMPLE III Efficiencyas an Internal Developer TABLE III Dev. B plus Dev. B plus Dev. A KI (.5 g./l.) NazSzOa g ./l.)

Rel. l Rel. Rel. speed Dmax. Dev. B speed* 'Dmax. speed" Dam 100 1.66 No image.-. 4. 6 0.32 3.8 0. 28

Speed measured at density=0.2 above tog.

This example, as manifested by the results, shows that the developer solution,'in accordance with the invention, is an etficient internal developer. The example further shows .that the addition of KI or Na S O alone to the conventional surface developer solution does not readily convert it to an efiicient internal developer.

EXAMPLE IV Comparative Example Each of three samples of Emulsion B are coated and exposed as in Example III. The exposed coatings are developed under optimum time and temperature conditions employing Developer A and two known iodideetching developers having the composition as follows.

Water to make 1 1.

Developer C is disclosed in Photo. Sci. Eng, I, 304 (1963). Developer D is disclosed by G. W. W. Stevens in Photographic Sensitivity, J. W. Mitchell, Ed., Butterworth, London, 1951.

The results of exposure and processing are summarized in Table IV.

TABLE IV Emulsion B Strip 1 Strip 2 Strip 3 Developer A C D Time of development (min.) 12 25 5 Temperature 0.) 15 40 Relative speed 100 50 23 D... 1. 85 1. 40 1.68

The results show that the developer of this invention is superior, for internal development, to the known iodideetching developers.

EXAMPLE V Comparative Example Samples of Emulsion A which are surface sensitized as in Example II are exposed and processed as in Example II employing Developer A with and without potassium iodide. The results as summarized in'Table V show that the developer of this invention comprising potassium iodide is superior to that'of the developer without potassium iodide. The results also show that filmf'pr'ocessed in the developer of this invention show increased Dmax.

TABLE V A t DeveloperA Developer A (excluding KI) Relative Relative Emulsion A speed max; speed Dim.

Sample 1 100 1. B3 Sample 2 34 1. 67

EXAMPLE VI Comparative Example The following developers are prepared:

Developer No. Composition Developer A.

. As No. 1 but without 1-pheny1-5-mercaptotetrezole;

3. As No. 1 except 10.0 g./l. NazSzOs replacing KI.

4. As No. 1 except 1.0 g./l. NazSsOs replacing KI.

5 As No. 1 except 0.002 g./l. KI.

6. As No. 1 except 0.002 g./l. KI and 0.01 g./l. 1-phenyl-5- mercaptotetrazole.

7 As No. 1 except 5-methyloxazoline-2-thiol replacing 1- phenyl-fi-mercaptotetrazole.

8 As N0. 1 except l-methyl-l,2,3,6,6-tetrahydro-1,3,5-triazine- 4-thiol replacing l-phenyl-5-mereaptotetrazole.

9 As N0. 1 except e-phenylimino-thlourazole replacing 1- phenyl-fi-mereaptotetrazole.

sults are measured and recorded in Table VI.

TABLE VI Developer Relative Shoulder No. speed Fog Dmnl; Gamma contrast Shoulder contrast is a measurement of the slope of a straight line drawn from the 0.5 density point on the characteristic curve to the density point on the curve obtained with 1.0 log E more exposure. Higher numbers indicate that greater density is obtained sooner, i.e. with less exposure.

The results illustrate that:

1. The best sensitometric properties are obtained with developer 1, 7, 8 and 9, i.e. the preferred developers of the instant invention. This is evident by the high contrast, both over-all and shoulder, as well as the best speed/fog ratio and Dmax. v

2. The replacement of potassium iodide with sodium thiosulfate reveals very poor internal development. Little change is noted by varying the concentration of Na S O i.e. 1.0 g./l. to 10.0 g./l. This is unexpected since these levels are generally within the optimum to obtain good internal development with conventional developing compositions.

3. Lower levels of potassium iodide do not effectively reveal the internal image, as evidenced in the date of Developers 5 and 6.

The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that-variations and modifications can be elfected within the spirit and scope of the invention.

;:;.WeClaim: :1. ;-.::1.- A.photographic'developer composition having a pH o'flat least about v12"comprising a 3-pyrazolidone, an ascorbicacid, and thecombination of a nitrogen containing heterocyclic thione or thiol compound with an alkali metal iodide of -about 0.002 to about 0.06moles per liter of said composition.

2 The photographic developer composition of Claim 1 wherein the heterocyclic thione or thiol compound is represented by the structural formula:

wherein Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing 5 to 6 atoms in the ring.

3. The photographic developer composition of Claim 1 wherein the heterocyclic thione or thiol is a S-mercaptotetrazole, an oxazoline-Z-thiol, a tetrahydro-1,3,5-triazine- 4-thiol or an iminothiourazole.

4. The photographic developer composition of Claim 3 wherein the heterocyclic thiol or thione compound is one of l-phenyl-S-mercaptotetrazole, 5 methyloxazoline 2- thiol, 1-methyl-1,2,3,6-tetrahydro-1,3,5-triazine-4-thiol or 4-phenyliminothiourazole.

5. The photographic developer composition of Claim 1 wherein said alkali metal iodide is potassium iodide.

6. The photographic developer composition of Claim 1 wherein said 3-pyrazolidone is 1-phenyl-3-pyrazolidone.

7. The photographic developer composition of Claim 1 wherein said 3-pyrazolidone is 1-phenyl-3-pyrazolidone, said ascorbic acid is sodium isoascorbate, said alkali metal iodide is potassium iodide and said heterocyclic thione or thiol is 1-phenyl-5-mercaptotetrazole.

8. A photographic developer composition as in Claim 1 wherein the alkali metal iodide, thione or thiol heterocyclic compound ratio is from about 3: 100 to about 600: 1.

9. A photographic developer composition as in Claim 1 12 wherein the potassium iodide, mercaptotetrazole mole rati is from about 9:100 to about 600:1..

10. A photographic developer composition as'in Claim 5 further comprising sodium sulfite andpotassium bromide.

11. A photographic developer composition as in Claim 1 wherein the ascorbic acid is sodium isoascorbate.

12. An aqueous photographic developer composition comprising about .06 moles 1-phenyl-3-pyrazo1idone, about .20 moles sodium isoascorbate, about .75 moles sodium hydroxide, about .16 moles sodium sulfite, about .0014 moles 1-phenyl-4-mercaptotetrazole, about .04, moles potassium bromide and about..003 moles potzissiumiodide.

13. A process of developing an exposed photographic element comprising surface sensitive and or internally sensitive silver halide materials with the developer solution of Claim 1.

14. A process of Claim 13 wherein said element comprises silver halide grains which form internal latent images.

15. A process of developing an exposed photographic element comprising internally sensitive silver bromoiodide materials with the developer composition of Claim 12.

16. A process of Claim 15 wherein said silver bromoiodide materials contain iridium ions occluded therein.

References Cited UNITED STATES PATENTS Stautfer 9664 RONALD H. SMITH, Primary Examiner M. F. KELLEY, Assistant Examiner US. (31. xii. 9666.3 

